Implausible Time Records

These dropouts never occur during engine run which normally only runs 10
minutes or less from engine start to shutdown after takeoff.

Heating up the dielectric is something I didn't consider.Â* Maybe I
should replace the antennae...

On 5/6/2019 11:39 AM, kinsell wrote:
On 5/6/19 10:32 AM, Dan Marotta wrote:
I've also had drop outs with my Trig TN-70 and its antenna, though
not as often as with my soaring GPSs.

Do they correlate with the engine running?Â* If so, might be ignition
noise.



Yes, the wires are tiny, but it was pretty simple to desolder them
from the puck, clip the cable to length, strip, tin, and solder.Â* I
did that for 3 antennae and they generally work fine, but lately have
acting up.

It's easy to overheat the dielectric in the coax, causing loss of
signal strength.



I'm looking at THESE
https://www.amazon.com/CIROCOMM-Antenna-Ceramic-25x25x2mm-Geekstory/dp/B078Y2WNY6?ref_=Oct_TopRatedC_3248676011_1&pf_rd_p =57ac2d87-b669-53fa-a2b6-2c15e8d66f28&pf_rd_s=merchandised-search-6&pf_rd_t=101&pf_rd_i=3248676011&pf_rd_m=ATVPDKIKX 0DER&pf_rd_r=GNQVSWJ3FAVNDTDDJJDS&pf_rd_r=GNQVSWJ3 FAVNDTDDJJDS&pf_rd_p=57ac2d87-b669-53fa-a2b6-2c15e8d66f28
as replacements.Â* Any comments?Â* I wonder if that IPEX connector is a
push fit on the built in SMA connectors on the devices. I'm also
considering replacing the modified antennae with factory new units
and using the longer cables to mount them on opposite canopy rails in
the Stemme.Â* Those should be about a meter apart.

On 5/6/2019 9:44 AM, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a
400 nm radius.Â* If you're getting bad time stamps just at liftoff,Â*
it's not likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to
be working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges
out to about 400 nm.Â* Moriarty is well within that area.Â* I've
asked other local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a
look at a divider for everything except the ADS-B WAAS GPS.Â* Its
antenna is mounted aft of the engine in the Stemme. The rest are on
or under the glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS. Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS". The
PowerFlarm portable screen also went blank with a "Zero
satellites" message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the
time.

After B190339 the time jumps back toÂ* B190337, which is odd, and
leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in
future by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be
shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to
happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that
it is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has
a shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim



--
Dan, 5J


--
Dan, 5J

Returning to the original problem, the warning from OLC is not particularly
helpful. The only problem detected was the out-of-sequence times. If these
were caused by corruption of the GPS signal, it should not affect the time
record. A failure of GPS signal will be shown in the IGC file as a zero GPS
altitude. This is not the case, therefore we can take it that it is not a
GPS problem.

As the time error occurred during take-off, when the glider was only a few
feet AGL, it was long before the start of the ‘Soaring Performance’, so
OLC is being a bit pedantic. I very much doubt if a Badge Claim would have
noticed this. SeeYou just skips over it.

I see this as a problem owned by ClearNav, although I have seen similar
time sequence errors in other recorders over the years. It will be
interesting to see if it reappears with the latest firmware.

Tim.
--
At 22:20 06 May 2019, Dan Marotta wrote:
These dropouts never occur during engine run which normally only runs 10
minutes or less from engine start to shutdown after takeoff.

Heating up the dielectric is something I didn't consider.Â* Maybe I
should replace the antennae...

On 5/6/2019 11:39 AM, kinsell wrote:
On 5/6/19 10:32 AM, Dan Marotta wrote:
I've also had drop outs with my Trig TN-70 and its antenna, though
not as often as with my soaring GPSs.

Do they correlate with the engine running?Â* If so, might be ignition
noise.



Yes, the wires are tiny, but it was pretty simple to desolder them
from the puck, clip the cable to length, strip, tin, and solder.Â* I
did that for 3 antennae and they generally work fine, but lately have
acting up.

It's easy to overheat the dielectric in the coax, causing loss of
signal strength.




On 5/6/2019 9:44 AM, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a
400 nm radius.Â* If you're getting bad time stamps just at liftoff,Â*

it's not likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to
be working on.

No help from ClearNav (yet).Â* I've updated the CNvXC firmware but not
flown with it yet.Â* It's overcast here...Â* As stated elsewhere, I'll
snug the connectors with a wrench (spanner), and I've relocated the
antenna pucks further apart, though a local pilot tells me he has four
antennae lined up next to each other and has no problems with reception.

Elsewhere I said that I don't have drop outs with the engine running.Â*
That was not entirely true.Â* I've had drop outs during repositioning
flights over the Rocky Mountains at 18,000' MSL.Â* It's very annoying but
I can see where I'm going and I'm not scoring those flights.

If I lose any more flights, I'll have to buy new antennae...

On 5/7/2019 2:21 AM, Tim Newport-Peace wrote:
Returning to the original problem, the warning from OLC is not particularly
helpful. The only problem detected was the out-of-sequence times. If these
were caused by corruption of the GPS signal, it should not affect the time
record. A failure of GPS signal will be shown in the IGC file as a zero GPS
altitude. This is not the case, therefore we can take it that it is not a
GPS problem.

As the time error occurred during take-off, when the glider was only a few
feet AGL, it was long before the start of the ‘Soaring Performance’, so
OLC is being a bit pedantic. I very much doubt if a Badge Claim would have
noticed this. SeeYou just skips over it.

I see this as a problem owned by ClearNav, although I have seen similar
time sequence errors in other recorders over the years. It will be
interesting to see if it reappears with the latest firmware.

Tim.

--
Dan, 5J

On Tuesday, May 7, 2019 at 4:30:05 AM UTC-4, Tim Newport-Peace wrote:
... I have seen similar time sequence errors in other recorders over the years...

IIRC I've seen this from a number of GPS engines;
certainly I've got some Garmin engine logs like this.
The problem is naive software that doesn't filter
'obviously' wrong stuff from the GPS engine, including
time going backwards and stupendous position jumps.
Some nice example traces here momentarily detour
from Montana into the North Atlantic for example...

None of my collected examples were (to my best
understanding) related to jamming.

Its important not to trust too much the inputs ;-)

See ya, Dave

On 5/7/19 10:10 AM, Dave Nadler wrote:
On Tuesday, May 7, 2019 at 4:30:05 AM UTC-4, Tim Newport-Peace wrote:
... I have seen similar time sequence errors in other recorders over the years...

IIRC I've seen this from a number of GPS engines;
certainly I've got some Garmin engine logs like this.
The problem is naive software that doesn't filter
'obviously' wrong stuff from the GPS engine, including
time going backwards and stupendous position jumps.
Some nice example traces here momentarily detour
from Montana into the North Atlantic for example...

None of my collected examples were (to my best
understanding) related to jamming.

Its important not to trust too much the inputs ;-)

See ya, Dave


I can't fault software for failing to filter out bad data. Having
submitted a number of logs to OLC from a cell phone, I don't see the
type of errors described here. Maybe better gps engines are in order?
Seems like producing good data is better than filtering out bad data.

I can't fault software for failing to filter out bad data.Â* Having
submitted a number of logs to OLC from a cell phone, I don't see the
type of errors described here.Â* Maybe better gps engines are in order?
Seems like producing good data is better than filtering out bad data.

What you say has merit, but I can't see opening up my ClearNav computer
and vario and attempting to replace the GPS engines.

Since both and my PowerFlarm portable experience the drop outs, I've got
three new antennae on order.Â* We'll see how that works.

Funny how this just started happening in the end of April...
--
Dan, 5J

On Wed, 08 May 2019 08:58:39 -0600, Dan Marotta wrote:

Funny how this just started happening in the end of April...

I thought: have you got another logger you could leave running on the
field away from the runway but where it gets a decent signal?

If that also gets the time hiccup, then you'll know the problem is
outside the Stemme.


--
Martin | martin at
Gregorie | gregorie dot org

I have a Dell Streak in the cockpit (right side) for my wife's use. It
also records an igc file which I can post on skylines.org.Â* It is not
acceptable to OLC due to no ENL recorder.Â* Maybe the XCSoar troops would
write a module to access the Streak's microphone and record engine
noise...Â* Or maybe one of the XCSoar clones already does that?

On 5/8/2019 12:16 PM, Martin Gregorie wrote:
On Wed, 08 May 2019 08:58:39 -0600, Dan Marotta wrote:

Funny how this just started happening in the end of April...

I thought: have you got another logger you could leave running on the
field away from the runway but where it gets a decent signal?

If that also gets the time hiccup, then you'll know the problem is
outside the Stemme.



--
Dan, 5J

Looking at your flight logs on OLC, you have the last two that didn't
validate, but others earlier this year that did.

However, most of the altitude graphs are plotted with many hours of dead
time, with the flight being compressed into the very right hand part of
the graph. A very bizarre presentation.

Perhaps your ClearNav has a hardware fault that is gradually getting worse?



On 5/6/19 4:20 PM, Dan Marotta wrote:
These dropouts never occur during engine run which normally only runs 10
minutes or less from engine start to shutdown after takeoff.

Heating up the dielectric is something I didn't consider.Â* Maybe I
should replace the antennae...

On 5/6/2019 11:39 AM, kinsell wrote:
On 5/6/19 10:32 AM, Dan Marotta wrote:
I've also had drop outs with my Trig TN-70 and its antenna, though
not as often as with my soaring GPSs.

Do they correlate with the engine running?Â* If so, might be ignition
noise.



Yes, the wires are tiny, but it was pretty simple to desolder them
from the puck, clip the cable to length, strip, tin, and solder.Â* I
did that for 3 antennae and they generally work fine, but lately have
acting up.

It's easy to overheat the dielectric in the coax, causing loss of
signal strength.



I'm looking at THESE
https://www.amazon.com/CIROCOMM-Antenna-Ceramic-25x25x2mm-Geekstory/dp/B078Y2WNY6?ref_=Oct_TopRatedC_3248676011_1&pf_rd_p =57ac2d87-b669-53fa-a2b6-2c15e8d66f28&pf_rd_s=merchandised-search-6&pf_rd_t=101&pf_rd_i=3248676011&pf_rd_m=ATVPDKIKX 0DER&pf_rd_r=GNQVSWJ3FAVNDTDDJJDS&pf_rd_r=GNQVSWJ3 FAVNDTDDJJDS&pf_rd_p=57ac2d87-b669-53fa-a2b6-2c15e8d66f28
as replacements.Â* Any comments?Â* I wonder if that IPEX connector is a
push fit on the built in SMA connectors on the devices. I'm also
considering replacing the modified antennae with factory new units
and using the longer cables to mount them on opposite canopy rails in
the Stemme.Â* Those should be about a meter apart.

On 5/6/2019 9:44 AM, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a
400 nm radius.Â* If you're getting bad time stamps just at liftoff,
it's not likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to
be working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges
out to about 400 nm.Â* Moriarty is well within that area.Â* I've
asked other local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a
look at a divider for everything except the ADS-B WAAS GPS.Â* Its
antenna is mounted aft of the engine in the Stemme. The rest are on
or under the glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS. Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS". The
PowerFlarm portable screen also went blank with a "Zero
satellites" message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the
time.

After B190339 the time jumps back toÂ* B190337, which is odd, and
leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in
future by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be
shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to
happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that
it is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has
a shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim



--
Dan, 5J

An interesting thought, but I see the same whether I'm using the
ClearNav or the ClearNav vario.Â* I doubt both could be experiencing the
same fault at the same time.Â* It's really odd about the apparent time
compression on the OLC display.Â* My flights score and appear just fine
on skylines.aero.

On 5/7/2019 8:21 AM, kinsell wrote:
Looking at your flight logs on OLC, you have the last two that didn't
validate, but others earlier this year that did.

However, most of the altitude graphs are plotted with many hours of
dead time, with the flight being compressed into the very right hand
part of the graph. A very bizarre presentation.

Perhaps your ClearNav has a hardware fault that is gradually getting
worse?



On 5/6/19 4:20 PM, Dan Marotta wrote:
These dropouts never occur during engine run which normally only runs
10 minutes or less from engine start to shutdown after takeoff.

Heating up the dielectric is something I didn't consider.Â* Maybe I
should replace the antennae...

On 5/6/2019 11:39 AM, kinsell wrote:
On 5/6/19 10:32 AM, Dan Marotta wrote:
I've also had drop outs with my Trig TN-70 and its antenna, though
not as often as with my soaring GPSs.

Do they correlate with the engine running?Â* If so, might be ignition
noise.



Yes, the wires are tiny, but it was pretty simple to desolder them
from the puck, clip the cable to length, strip, tin, and solder.Â* I
did that for 3 antennae and they generally work fine, but lately
have acting up.

It's easy to overheat the dielectric in the coax, causing loss of
signal strength.



I'm looking at THESE
https://www.amazon.com/CIROCOMM-Antenna-Ceramic-25x25x2mm-Geekstory/dp/B078Y2WNY6?ref_=Oct_TopRatedC_3248676011_1&pf_rd_p =57ac2d87-b669-53fa-a2b6-2c15e8d66f28&pf_rd_s=merchandised-search-6&pf_rd_t=101&pf_rd_i=3248676011&pf_rd_m=ATVPDKIKX 0DER&pf_rd_r=GNQVSWJ3FAVNDTDDJJDS&pf_rd_r=GNQVSWJ3 FAVNDTDDJJDS&pf_rd_p=57ac2d87-b669-53fa-a2b6-2c15e8d66f28
as replacements.Â* Any comments?Â* I wonder if that IPEX connector is
a push fit on the built in SMA connectors on the devices. I'm also
considering replacing the modified antennae with factory new units
and using the longer cables to mount them on opposite canopy rails
in the Stemme.Â* Those should be about a meter apart.

On 5/6/2019 9:44 AM, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a
400 nm radius.Â* If you're getting bad time stamps just at liftoff,
it's not likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires
to be working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges
out to about 400 nm.Â* Moriarty is well within that area.Â* I've
asked other local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship. I'll take
a look at a divider for everything except the ADS-B WAAS GPS.Â*
Its antenna is mounted aft of the engine in the Stemme. The rest
are on or under the glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS. Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS". The
PowerFlarm portable screen also went blank with a "Zero
satellites" message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the
time.

After B190339 the time jumps back toÂ* B190337, which is odd,
and leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in
future by
setting a longer fix interval, even 2 seconds might help, but
no promises.

I am not seeing any GPS outage around that time. This would be
shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to
happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just
that it is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna
has a shortened cable to a MECA divider, then a short SMA-SMA
link cable.
Jim



--
Dan, 5J




--
Dan, 5J